1. Field of the invention
The present invention relates to the optoelectronic connectivity and more specifically, the interconnection of an optical array to fiber optic bundles.
2. Background Art
As processing speeds increase and technology improves, data is being transferred at very high rates. However, one problem with high into data transfer is that each leg in the process must be capable of the high rate transfer or a bottleneck occurs. This problem holds true for data transfer within an integrated circuit, from one chip to another, from one integrated circuit board to another, and from system to system.
In the field of high-speed communications, increasing data transmission rates have been hindered by the limitations posed by fiber optics connectivity. In particular, increasing transmission density is difficult because the number of data transmission lines that conventional packaging technologies can handle is limited.
Glass fiber array pigtails can be used to couple light between two-dimensional optoelectronic arrays and fiber optics. However, the use of glass fibers is prohibitively expensive and glass fiber has associated tolerance stack-up issues. Thus, there are known problems when coupling light between optoelectronic arrays and fiber optics.
Glass fiber array pigtails can be also be used to couple light between two-dimensional optoelectronic arrays and fiber optics, but the extremely high bend radius of glass fiber requires significant clearance above the active device, which is not desirable in high-density packaging. Glass fibers cannot accommodate sharper bends and therefore limits electronic packaging. Other waveguide types utilize mirrors and complicated assemblies to redirect the light beams until the light is properly oriented for reception by an optical fiber.
An additional connectivity problem involves the X and Y pitch of a two-dimensional optoelectronic array that usually differs from the pitch of a standard fiber ribbon. Waveguides with constant pitch therefore are unable to couple light from a nonstandard pitch optoelectronic array to a standard fiber ribbon. One alternative is to limit the pitch of the array to match the footprint of the optical connectors, however this would increase the size of the array and decrease the output potential of the array.
There have been attempts to address the mismatch problem between optical arrays and optical connectors, but they have met with limited success. In general, there are many optical coupling devices that provide connectivity between fiber optic cables and terminate optical fiber cables, such as U.S. Pat No. 5,909,526. There are also schemes for connecting electro-optics that employ complex coordination and alignment problems such as U.S. Pat. No. 5,579,426. But, the prior art still does not address interconnecting to an industry standard connector. As a connector type is adopted and approved as a standard, manufacturers and designers rush to incorporate the connector type to allow standardization in the industry. Thus far there has been a mismatch between the array technology and the connector types in use.
Thus, there is a need for a way to couple light between optoelectronic arrays and fiber optics. There is a also a need for a way to bend the light from one plane to another in a minimum turn radius in order to keep the headroom adequate for packaging considerations. In addition, there is a need for a way to transition from the pitch of a two-dimensional optoelectronic array to the pitch of a standard fiber ribbon to permit industry standard connectorization. What is needed is a method and apparatus for utilizing the advantages of optical technology and providing a mechanism to efficiently interconnect to industry standard connectors such that the electronics industry can fully exploit the bandwidth, speed and efficiency of optics.
The invention is devised in the light of the problems of the prior art described herein. Accordingly it is a general object or the present invention to provide a novel and useful technique that can solve the problems described herein. In general, one object of the invention provides an optical waveguide assembly that includes a waveguide housing supporting a plurality of waveguide sheets (each including a 1xc3x97N array of waveguides), feeding a plurality of industry standard 2xc3x97N ferrules.
The present invention features a waveguide assembly that couples light from a two-dimensional optoelectronic array to standard fiber optic ribbon bundles. The invention features a waveguide assembly that provides a low profile angular transition from a two-dimensional optoelectronic array to fiber optic bundles. Further, the invention features a waveguide assembly that provides a pitch transition from an optoelectronic array to a standard fiber ribbon.
In general, in still another aspect, the invention features a waveguide assembly that is easily scalable to various optoelectronic array configurations. For example, an 8xc3x9712 array can be separated as illustrated herein to mate with the industry standard 2xc3x9712 ferrules. It should be appreciated that as the channel count and pitch spacing of the connector end increase, the present invention is adaptable to new counts and pitch. It is expected that as the connector technology improves, the optoelectronic array technology may also improve and have a continuing need for matching high density high channel count arrays to industry standard connectors.
An object of the invention is an optical waveguide assembly providing an interface between a two-dimensional optoelectronic array and an optical connector, comprising two or more waveguide sheets having an array end and a connector end, wherein each of the waveguide sheets has a plurality of one-dimensional waveguides, and wherein the waveguides at the array end match an optoelectronic array footprint and the waveguides at the connector end match a connector footprint.
Another object is the optical waveguide assembly, further comprising a waveguide housing assembly retaining the waveguide sheets and controlling a row spacing between the waveguide sheets to match the optoelectronic footprint. In addition, further comprising an anchor plate that interconnects with the waveguide housing.
A further object is the optical waveguide assembly, wherein a pitch between each of the waveguides is designed to match the optoelectronic footprint and the connector footprint. Also, wherein the waveguide sheets are generally rectangular and have a protrusion, wherein the waveguides terminate at the protrusion.
The optical waveguide assembly, wherein the waveguides are bendable within the waveguide sheets. The bend can exceed 90 degrees depending upon the waveguide sheet material, waveguide sheet length and amount of acceptable loss. In general, the bending radius should be as large as possible to minimize loss, however the waveguides permit tighter bends than glass fibers.
In addition, an object is the optical waveguide assembly, wherein the waveguide sheets are grouped at the connector end to connect to one or more ferrules. Although 2xc3x9712 ferrules are described, other ferrules and connectors are within the scope of the invention.
An object of the present invention is to provide a low-profile optical assembly for interfacing a two-dimensional optoelectronic array to an optical connector, comprising two or more flexible waveguide sheets, wherein each of the waveguide sheets has an array end and a connector end. There are a plurality of one-dimensional waveguides in each of the waveguide sheets, wherein each of the waveguides has an array end pitch at the array end and a connector end pitch at the connector end, and wherein the array end pitch matches a pitch of the optoelectronic array and the connector end pitch matches a pitch of the optical connector. There is also a waveguide housing at the array end of the waveguide sheets for retaining the waveguide sheets, wherein each of the waveguide sheets has an array end spacing at the array end and a connector end spacing at the connector end, and wherein the array end spacing matches a spacing at the optoelectronic array and the connector end spacing matches a spacing at the optical connector.
Another object is the low-profile optical assembly, further comprising an anchor plate that interconnects with the waveguide housing. The waveguide sheets being generally rectangular and having a protrusion extending beyond a plane of the anchor plate, wherein the waveguides terminate in the protrusion.
Still other objects and advantages of the present invention will become readily apparent to those skilled in this art from the following detailed description, wherein we have shown and described only a preferred embodiment of the invention, simply by way of illustration of the best mode contemplated by us on carrying out our invention. As will be realized, the invention is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, all without departing from the invention.